Conventional apparatuses of this type include a multicast tree design apparatus that designs a multicast tree by using Dijkstra's algorithm. Dijkstra's algorithm is an algorithm for selecting a route that minimizes a defined cost. Dijkstra's algorithm has been suitably used to design a multicast tree so as to minimize the link cost from a source node to a plurality of destination nodes.
There has been proposed an apparatus that designs a multicast tree in a mixed network of nodes having a multicast forwarding function and nodes having only a unicast forwarding function. Using an improved Dijkstra's algorithm, the apparatus designs a multicast tree so as to reduce the link cost from a source node to a plurality of destination nodes as well as to prevent the occurrence of branching at the nodes that only have a unicast function (for example, see PTL 1).
Methods for designing optimum paths in a communication network by using mathematical programming have also been known. For example, according to a design method described in PTL 2, a route control apparatus develops the path allocation scheme of an arbitrary network configuration along the framework of linear programming, and applies various types of linear programming solutions to determine path allocations, flow bandwidths, and objective function values for comparative evaluation. A method of designing a network that consists of node-connecting links by mathematical programming has been shown, for example, in PTL 3.
{Citation List}
{Patent Literature}
    {PTL 1} JP-A-2007-6228    {PTL 2} JP-B-3782063    {PTL 3} JP-B-3141808